hush: make "set -x" output closer to bash

function                                             old     new   delta
print_optionally_squoted                               -     145    +145
run_pipe                                            1902    1919     +17
dump_cmd_in_x_mode                                   142     110     -32
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 1/1 up/down: 162/-32)           Total: 130 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 60 insertions, 18 deletions

diff --git a/shell/hush.c b/shell/hush.c
index e9212cefc..ac8467fb4 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -8030,28 +8030,67 @@ static void execvp_or_die(char **argv)
 }
 
 #if ENABLE_HUSH_MODE_X
+static void print_optionally_squoted(FILE *fp, const char *str)
+{
+        unsigned len;
+        const char *cp;
+
+        cp = str;
+        if (str[0] != '{' && str[0] != '(') for (;;) {
+                if (!*cp) {
+                        /* string has no special chars */
+                        fputs(str, fp);
+                        return;
+                }
+                if (*cp == '\\') break;
+                if (*cp == '\'') break;
+                if (*cp == '"') break;
+                if (*cp == '$') break;
+                if (*cp == '!') break;
+                if (*cp == '*') break;
+                if (*cp == '[') break;
+                if (*cp == ']') break;
+#if ENABLE_HUSH_TICK
+                if (*cp == '`') break;
+#endif
+                if (isspace(*cp)) break;
+                cp++;
+        }
+
+        cp = str;
+        for (;;) {
+                /* print '....' up to EOL or first squote */
+                len = (int)(strchrnul(cp, '\'') - cp);
+                if (len != 0) {
+                        fprintf(fp, "'%.*s'", len, cp);
+                        cp += len;
+                }
+                if (*cp == '\0')
+                        break;
+                /* string contains squote(s), print them as \' */
+                fprintf(fp, "\\'");
+                cp++;
+        }
+}
 static void dump_cmd_in_x_mode(char **argv)
 {
         if (G_x_mode && argv) {
-                /* We want to output the line in one write op */
-                char *buf, *p;
-                unsigned len;
                 unsigned n;
 
-                len = G.x_mode_depth + 3; /* "+[+++...][ cmd...]\n\0" */
-                n = 0;
-                while (argv[n])
-                        len += strlen(argv[n++]) + 1;
-                p = buf = xmalloc(len);
+                /* "+[+++...][ cmd...]\n\0" */
                 n = G.x_mode_depth;
-                do *p++ = '+'; while ((int)(--n) >= 0);
+                do bb_putchar_stderr('+'); while ((int)(--n) >= 0);
                 n = 0;
-                while (argv[n])
-                        p += sprintf(p, " %s", argv[n++]);
-                *p++ = '\n';
-                *p = '\0';
-                fputs(buf, stderr);
-                free(buf);
+                while (argv[n]) {
+                        if (argv[n][0] == '\0')
+                                fputs(" ''", stderr);
+                        else {
+                                bb_putchar_stderr(' ');
+                                print_optionally_squoted(stderr, argv[n]);
+                        }
+                        n++;
+                }
+                bb_putchar_stderr('\n');
         }
 }
 #else
@@ -8845,13 +8884,18 @@ static NOINLINE int run_pipe(struct pipe *pi)
                                 );
 #if ENABLE_HUSH_MODE_X
                                 if (G_x_mode) {
+                                        char *eq;
                                         if (i == 0) {
                                                 unsigned n = G.x_mode_depth;
                                                 do
                                                         bb_putchar_stderr('+');
                                                 while ((int)(--n) >= 0);
                                         }
-                                        fprintf(stderr, " %s", p);
+                                        eq = strchrnul(p, '=');
+                                        fprintf(stderr, " %.*s=", (int)(eq - p), p);
+                                        if (*eq)
+                                                print_optionally_squoted(stderr, eq + 1);
+                                        bb_putchar_stderr('\n');
                                 }
 #endif
                                 debug_printf_env("set shell var:'%s'->'%s'\n", *argv, p);
@@ -8861,8 +8905,6 @@ static NOINLINE int run_pipe(struct pipe *pi)
                                 }
                                 i++;
                         }
-                        if (G_x_mode)
-                                bb_putchar_stderr('\n');
                         /* Redirect error sets $? to 1. Otherwise,
                          * if evaluating assignment value set $?, retain it.
                          * Else, clear $?: